Alert archive / Montana / Special Weather Statements in 2021

Special Weather Statement, NWS Missoula, MT

November 7, 2021Lake County, Montana

NWS Missoula, MT issued this special weather statement at Nov 7, 2021, 4:13 AM MST for Lake County, Montana. It was in force for 47 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Nov 7, 2021, 4:13 AM MST (11:13 UTC)
Expired
Nov 7, 2021, 5:00 AM MST
In force
47 min
Issued by
NWS Missoula, MT
Hail
0.00 in
Wind
30

County Lake County, MT

The radar

The Missoula radar (KMSX), 29 km from the middle of the area, began a volume at 11:13 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Spokane, WA (KOTX), launched 00:00Z, 11.2 hours before the alert went out and 201 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Spokane, WA at 00:00Z on 2021-11-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 43 joules per kilogram.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Spokane, WA at 00:00Z on 2021-11-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 77 square meters per square second.1939587897117Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
43 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
825 m above ground
0-6 km bulk shear
60 kt
0-1 km storm-relative helicity
77 m²/s²
0-3 km storm-relative helicity
96 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

As transmitted.

897 
WWUS85 KMSO 071113
SPSMSO

Special Weather Statement
National Weather Service Missoula MT
413 AM MST Sun Nov 7 2021
 
MTZ002>004-043-071200-
Flathead/Mission Valleys MT-West Glacier Region MT-
Lower Clark Fork Region MT-Potomac/Seeley Lake Region MT-
413 AM MST Sun Nov 7 2021

...An intense snow shower will impact portions of southeastern Lake,
northeastern Missoula, southeastern Flathead and western Powell
Counties through 500 AM MST...

At 412 AM MST, Doppler radar was tracking an intense snow shower 8
miles northeast of Arlee, or 25 miles north of Missoula, moving
northeast at 25 mph.

HAZARD...Visibility one-half mile or less.

SOURCE...Radar indicated.

IMPACT...Low visibility with moderate to heavy snow could result in 
         dangerous driving conditions.

Locations impacted include...
Ravalli, Arlee, Seeley Lake, and Condon. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 4709 11404 4727 11419 4769 11357 4722 11317
TIME...MOT...LOC 1112Z 241DEG 22KT 4724 11394 

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...<30 MPH

$$

Nearby

Special Weather Statements in Montana, 2021Every special weather statement in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.